Multi-tiered, modular racks are commonly used with groups of modular chassis. Such racks commonly provide each chassis with access to network connections and electrical power. A typical chassis might contain components and interconnecting devices (e.g., printed circuit board cards and wires) that form a computer system such as a server. Each chassis functions to provide an environment relatively free from excessive heat, shock, vibration and/or dust for the computer system. Groups of these computer systems are interconnected to form electronic applications, such as server farms that serve the networking needs of large organizations.
In present-day, standardized racks, 1U “pizza-box” chassis (being approximately 1.7 inches tall, and various lateral sizes such as 19 by 24 inches), each housing a separate computer having one or more CPUs, are found to be useful. In particular, the small form factor (i.e., size) allows for a large number of computers to be vertically stacked, with up to around 40U or 42U, in each rack. The modular nature of each such chassis allows for a given computer system to be swapped out of the network and the rack without interfering with the operation of other computer systems.
Each chassis typically has one or more air movers (e.g., fans) that pump ambient air through the chassis to absorb heat from the components, or from heat sinks attached to the components. In response to demands for networks of high-performance computer systems, components are being designed with increased cooling requirements, and printed circuit boards are being designed with increased component densities. Managing these increased heat-dissipation requirements is complicated by the limited size of the 1U chassis. In particular, the small form factor limits both the available fan sizes and the space for air to flow through the chassis. The limited space typically includes many impediments, such as heat sinks, wires and components, causing significant airflow impedance. As a result, the airflow through the chassis can be significantly limited, thereby limiting the dissipation ability of the chassis cooling system. Furthermore, the tight space configuration can create cooling issues such as hot spots, dead zones and/or insufficient cooling capacity in particular chassis locations.
It will therefore be appreciated that there is a need for a cooling system and apparatus for effectively cooling the heat-dissipating components housed within a 1U chassis in multi-tiered, modular racks. There is also a need for a resulting modular rack system. Preferred embodiments of the present invention satisfy some or all of these needs, and provide further related advantages.